Silver brazing alloy containing indium



Patented Dec. 14, 1948 UNITED STATES PATENT OFFICE sILvER BRAZING ALLOY CONTAINING INDIUM Joseph F. -Pol ak;.Newark,, N. J assignor to Monroe Sherman New York, N.'Y.

NoDrawing. ,ApplicationMarch 22,1945,

"Serial No. 584,248

sclaiims; lous -.134). I

My invention relates generally to alloys used ture substantiallylower'than those'brazingalloys for brazing and similar purposes, and particucommercially available. larly relates to brazing alloys having relatively Asecond specific brazing alloy prepared in aclow melting and flow points. cordance with and embodying my invention is:

The main object of my invention is the pro- 5 Metal: Percent by weight vision of an alloy suitable for brazing, which alloy silver 4140 includes indium. Copper 1390 Another object of my invention is the provi- Zinc 1540 i n of a brazing alloy have a relatively low Cadmium 16A) melting and fiowpoint for use in brazing a wide Indium 1410 variety of materials, 1. e., pure metals or metal alloys. This specific brazlng alloy will become liquid oth object of my invention in be Obvious and free flowing at about 1035 R, which is lower from the following descriptions of illustrative than the first exampleembodiments thereof. I have found that good results may be obtained Many commercially available brazing alloys in my brazing alloy yi e a s mfi ant contain silver, copper, zinc and cadmium, but I amount of tin along h mdlumhave found that the addition of indium to these ever, When both tm and Ind-111m are used, the conventi-onally used metals makes for a brazing gregate amount thereof should not exceed 29% alloy having a much Wider field of utility than of the total we t of e ements in the braz n conventionally known brazing alloys. alloy- In the Second Specific fit pl P a braz- My new and improved ll is 11 adapted for ing alloy in accordance with my invention, I may use in processing eith pure t l or alloys include instead of the 14.10% of indium, 9.10%

thereof, and in the following specification, I will or of tin and 5% of indiumuse the term metals to indicate the materials Commercially kHQWn bra zlng alloys d the being brazed, Welded and/or soldered, both pure llke e a rather high melting and flow point of metals and alloys thereof. The term alloy will about 1175" which hr ts thelr l y 1n the be used t0 designate the material employed in brazing of metals wherein the crltlcal temperathe brazing, welding and/or soldering processes. tures would be re2}ched at abqut the tlme the I have found that brazing alloys prepared from m ajnoys become q and free flowmg' The ith t followin range are extremely u eful tlon of the application of heat and the degreeof having melting and flow points which are below heat are both factors to be consldered, and wlth the points at which a great variety of the matebrazmg alloys Wh1ch melt and flow at about rials it might be desired to braze may be harmed 11750 there 15 danger of damage to the metals by higher heat; 3.3 being brazed, because the critical temperatures of the steels and the annealing temperatures of Metal: Percent by weight non-ferrous metals may well be reached before Silver (Ag) to 48 the high temperature brazing alloys will melt and Copper (Cu) 10 to 15 flow. Zinc (Zn) 12 to 17 40 These conventional high temperature brazing Cadmium (Cd) a- 12 to 20 alloys cannot be safely used when it is desired Indium (In) 2.5 to 20 t make a second brazed joint in an assembly which has already been brazed, for the heat needed to make the second joint may cause a melting and flowing in the area of the first joint.

Further, thin metal sections being brazed with One specific example of a brazing alloy prepared according to and embodying my invention is:

the conventionally known high temperature i ji i g g alloys (i. e., those melting and flowing at about Copper 13.50 1175 F.) present their own particular problem, Zinc 1550 for the application of heat thereto is very difficult Cadmium 1650 to control and there is ever present the likelihood Indium 900 that the thin sections will be melted or otherwise damaged before the brazing alloys will melt and This particular brazing alloy will become liquid fiow.

and free flowing at about 1100" F., a tempera- My new and improved brazing alloy has amuch 3 wider field of utility than those heretofore known, for it will melt and flow at much lower temperatures; thin section materials may be operated upon with relatively little danger; a

number of joints may be brazed in the same general area; and the critical temperatures or annealing temperatures of the metals being worked upon need'not be approximated.

Having now described my invention, what I claim and desire to secure by Letters Patent is:

1. An alloy consisting of, by weight, silver be-; tween 35% and 48%, copper between 10% and l5%, zinc between 12% and 17%, cadmiumbetween 12% and 20%, and indium between'9%andl. v

20% with no other metals therein.

2. An alloy comprising, by weight, substantially 45.50% of silver, 13.50% of copper, 15.50%"012 1 zinc, 16.50% of cadmium and 9% of indium.

3. An alloy comprising, by weight, substantially x 41.40% of silver, 13% of copper, 15.10% of zinc, 2o 16.40% of cadmium and 14.10% of indium.

' JOSEPH F. PQLAK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name, Date 1,934,730 Murray Nov. 14, 1933 2,157,933 Hensel May 9, 1939 2,196,306 Hensel Apr. 9, 1940 2,235,634 ...I-Iense1 Mar. 18, 1941 2,288,654 Smart July 7, 1942 2,362,893 Durst Nov. 14, 1944 22,374,183 Durst Apr. 24, 1945 OTHER REFERENCES Steel, November 9, 1942, page 81.

Product Engineering, October 1943, pages 630, 

